JPH08239531A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE: To obtain the subject composition, comprising a copolymer containing a specific monomer component and specific two kinds of graft copolymers, well balanced among impact resistance, surface hardness and rigidity and useful as various industrial materials. CONSTITUTION: This resin composition comprises (A) a graft copolymer containing an aromatic alkenyl monomer, a vinyl cyanide monomer and a vinyl monomer copolymerizable therewith as constituent components, (B) a graft copolymer prepared by grafting a monomer mixture comprising an aromatic vinyl monomer, the vinyl cyanide monomer and vinyl monomer copolymerizable therewith onto a rubber polymer and (C) a graft copolymer obtained by grafting the aromatic alkenyl monomer, an acrylic or a methacrylic ester or the vinyl cyanide monomer onto a composite rubber comprising (C1 ) a polyorganosiloxane and (C2 ) a polyalkyl (meth)acrylate. The content of the component (B) or (C) is >40 pts.wt. based on 100 pts.wt. component (A).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an impact resistant resin composition having excellent impact resistance and rigidity.

[0002]

2. Description of the Related Art Improving the impact resistance of resin materials not only expands the applications of the materials, but also makes it possible to cope with thinner and larger molded products, which is of great industrial utility. The invention is large and has been invented by various methods.

In particular, a resin material in which a rubber component having a low Tg and a low elastic modulus is dispersed in a resin matrix has been industrialized due to its excellent impact resistance. Conventionally, ABS resin has been known as one of the materials having improved impact resistance by dispersing such a rubber component in a resin matrix.

The ABS resin is obtained by dispersing an ABS graft polymer obtained by graft-polymerizing acrylonitrile and styrene on polybutadiene in a SAN resin matrix. Taking advantage of its excellent physical property balance and moldability, it is used as various industrial materials. It's being used.

Further, the ABS graft polymer constituting the ABS resin is used as a modifier for imparting impact resistance by blending it with other resins such as polycarbonate resin and polyester resin.

However, the effect of the ABS graft polymer as an impact modifier is not always sufficient,
SAN resin, polycarbonate resin and SAN /
A resin composition using a polycarbonate blend as a matrix cannot be used for applications that are used under particularly severe conditions due to insufficient impact strength of molded products.

Further, as a method for improving the effect of the ABS graft polymer as an impact resistance modifier, and particularly for improving the impact strength in a low temperature atmosphere, JP-A-6-189.
No. 7 discloses a resin matrix composed of PC and / or copolyester carbonate and SAN resin.
There has been proposed a method of using a resin composition comprising a BS-graft polymer and a composite rubber-based graft copolymer obtained by graft-polymerizing a vinyl monomer onto a composite rubber containing a polyorganosiloxane and a polyalkyl acrylate.

[0008]

However, in Japanese Patent Laid-Open No. 6-1897, an ABS graft polymer and a polyorganosiloxane and a polyorganosiloxane and a polyorganosiloxane are added to a resin matrix composed of PC and / or copolyester carbonate and SAN resin. Although it has been shown that a resin composition obtained by combining a composite rubber-based graft copolymer obtained by graft-polymerizing a vinyl monomer to a composite rubber containing an alkyl acrylate has excellent impact resistance, the SAN resin alone is used. It has not been clarified how to improve the impact resistance of the resin matrix material.
Furthermore, ABS is used for 100 parts by weight of the matrix resin.
Although it is described that the graft polymer and the resin composition containing 5 to 40 parts by weight of each of the above composite rubber-based graft copolymers show excellent impact resistance and especially low temperature impact characteristics, the ABS graft polymer is A resin composition containing more than 40 parts by weight or a composite rubber-based graft copolymer in an amount exceeding 40 parts by weight is said to be unfavorable because of lowering of rigidity.

That is, conventionally, it is composed of a SAN resin matrix, an ABS graft polymer, and a composite rubber-based graft copolymer in which a vinyl monomer is graft-polymerized to a composite rubber containing a polyorganosiloxane and a polyalkyl acrylate. No method has been found for a resin composition containing an ABS graft polymer or a composite rubber graft copolymer in an amount exceeding 40 parts by weight and simultaneously satisfying high impact resistance and rigidity. , Development of the technique for improving this was strongly desired.

[0010]

DISCLOSURE OF THE INVENTION The present inventors have developed a composite rubber system in which a vinyl monomer is graft-polymerized to a SAN resin matrix, an ABS graft polymer, and a composite rubber containing a polyorganosiloxane and a polyalkyl acrylate. As a result of extensive studies on impact resistance and rigidity of the resin composition comprising the graft copolymer, surprisingly, SAN was found.
ABS graft polymer is added to 100 parts by weight of resin.
Use in an amount exceeding 0 part by weight and / or in an amount exceeding 40 parts by weight of a composite rubber-based graft copolymer in which a vinyl monomer is graft-polymerized to a composite rubber containing an organosiloxane and a polyalkyl acrylate. By
The present inventors have found that the ABS resin (SAN resin + ABS graft polymer) has improved impact resistance without impairing the good rigidity originally possessed by the ABS resin (SAN resin + ABS graft polymer), and arrived at the present invention.

That is, the gist of the present invention is that
In the thermoplastic resin composition comprising the following (A), (B) and (C), with respect to 100 parts by weight of the (C) copolymer,
A thermoplastic resin composition comprising (A) or (B) in an amount of more than 40 parts by weight.

(A) A graft copolymer obtained by grafting a rubber-like polymer with a monomer mixture of an aromatic alkenyl monomer, a vinyl cyanide monomer and a vinyl monomer copolymerizable therewith. .

A composite rubber composed of (B) (b-1) polyorganosiloxane and (b-2) polyalkyl (meth) acrylate is added to (b-3) an aromatic alkenyl monomer, a methacrylic acid ester, A graft copolymer in which one or more monomers selected from acrylic acid esters or vinyl cyanide monomers are graft polymerized.

(C) A copolymer comprising an aromatic alkenyl monomer component, a vinyl cyanide monomer component and a vinyl monomer component copolymerizable therewith as a constituent component of the copolymer.

Examples of the rubber-like polymer constituting the graft copolymer (A) according to the present invention include polybutadiene, polyisoprene, styrene-butadiene random copolymers and block copolymers, and hydrogen of the block copolymers. Additives, acrylonitrile-butadiene copolymers, butadiene-isoprene copolymers and other diene rubbers, ethylene-propylene random copolymers and block copolymers, ethylene-butene random copolymers and block copolymers, A copolymer of ethylene and α-olefin,
Acrylic ester-butadiene copolymer such as butyl acrylate-butadiene copolymer, acrylic elastomer such as cross-linked acrylate, ethylene-vinyl acetate copolymer,
Examples of the ethylene-propylene-ethylidene norbornene copolymer, ethylene-propylene non-conjugated diene-polymer such as ethylene-propylene-hexadiene copolymer, butylene-isoprene copolymer, chlorinated polyethylene, etc. Two or more types can be used. Considering the impact resistance and molding processability of the resulting resin composition, preferable rubber-like elastic materials include ethylene-propylene rubber, butyl acrylate-butadiene copolymer, acrylic elastic material, diene rubber, ethylene-propylene. It is a non-conjugated diene polymer, more preferably polybutadiene or butyl acrylate.
A butadiene copolymer and a styrene-butadiene copolymer.

The graft copolymer (A) according to the present invention is
A graft copolymer obtained by grafting a monomer mixture of an aromatic alkenyl monomer, a vinyl cyanide monomer, and a vinyl monomer copolymerizable therewith to the rubber-like elastic body, which is used. The aromatic alkenyl monomer is, for example, styrene, α-methylstyrene, vinyltoluene, etc., and the vinyl cyanide compound is, for example, acrylonitrile, methacrylonitrile, etc., and as a copolymerizable vinyl monomer. Are methyl methacrylate, ethyl methacrylate, methacrylic acid esters such as 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, acrylic acid esters such as butyl acrylate, maleimide compounds and the like, Considering the impact resistance of the resulting resin composition, the monomer used is preferably A mixture of alkylene and acrylonitrile.

The copolymer (C) according to the present invention comprises an aromatic alkenyl monomer component, a vinyl cyanide monomer component and a vinyl monomer component copolymerizable therewith as a constituent component of the copolymer. As the aromatic alkenyl monomer, a styrene, α-methylstyrene, vinyltoluene, monochlorostyrene, dichlorostyrene,
Monobromostyrene, dibromostyrene, p-tert-butylstyrene, ethylstyrene, vinylnaphthalene and the like are preferable, and styrene and α-methylstyrene are preferable. Examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile, and acrylonitrile is preferable. As the copolymerizable vinyl monomer, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate and glycidyl methacrylate, methyl acrylate, ethyl acrylate. , Acrylic acid esters such as butyl acrylate, maleimide compounds such as N-phenylmaleimide and N-methylmaleimide, and maleic anhydride. As a preferable example of the copolymer (C), a styrene-acrylonitrile copolymer (S
AN resin) and styrene-acrylonitrile-N-phenylmaleimide copolymer.

As the method for producing the copolymer (C), generally known methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization are used.

The composite rubber-based graft copolymer (B) according to the present invention is a composite rubber comprising a polyorganosiloxane and an alkyl (meth) acrylate rubber, an aromatic alkenyl monomer, a methacrylic acid ester, and an acrylic acid ester. Alternatively, it is a graft copolymer obtained by graft-polymerizing one or more monomers selected from vinyl cyanide monomers.

The polyorganosiloxane (b-1) constituting the copolymer (B) is not particularly limited, but preferably comprises a vinyl polymerizable functional group-containing siloxane unit and a dimethylsiloxane unit. It is a characteristic polydimethylsiloxane.

As the method for producing the polyorganosiloxane, a latex obtained by emulsifying a mixture of dimethylsiloxane and a vinyl-polymerizable functional group-containing siloxane or a mixture further containing a siloxane-based cross-linking agent with an emulsifier and water is subjected to shearing force by high-speed rotation. After homogenizing with a homomixer that atomizes with a homogenizer that atomizes with a high-pressure generator, etc., polymerize at high temperature with an acid catalyst, and then neutralize the acid with an alkaline substance. It is a thing.

The method of adding the acid catalyst used in the polymerization is as follows.
There are a method of mixing with a siloxane mixture, an emulsifier and water, and a method of dropping a latex in which the siloxane mixture is made into fine particles into a hot acid aqueous solution at a constant rate.
Considering the ease of controlling the particle size of the polyorganosiloxane, a method is preferred in which a latex in which the siloxane mixture is made into fine particles is dropped into the high temperature aqueous acid solution at a constant rate.

The size of the polyorganosiloxane is not particularly limited, but considering the pigment colorability of the resin composition containing the graft copolymer, the weight average particle diameter is preferably 0.2 μm or less, more preferably 0.1 μm. It is the following.

The dimethylsiloxane used for producing the polyorganosiloxane may be a dimethylsiloxane cyclic compound having a 3-membered ring or more, and a 3-membered to 6-membered ring is preferable. Specific examples thereof include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, etc. These may be used alone or in combination of two or more.

The vinyl-polymerizable functional group-containing siloxane has a vinyl-polymerizable functional group and can be bonded to dimethyl siloxane through a siloxane bond. Considering the reactivity with dimethyl siloxane, vinyl polymerization is possible. Various alkoxysilane compounds containing a functional group are preferred. Specifically, β-methacryloxyethyldimethoxymethylsilane, γ-methacryloxypropyldimethoxymethylsilane, γ-methacryloxypropylmethoxydimethylsilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylethoxydiethylsilane, Methacryloxysiloxanes such as γ-methacryloxypropyldiethoxymethylsilane and δ-methacryloxybutyldiethoxymethylsilane, vinylsiloxanes such as tetramethyltetravinylcyclotetrasiloxane, p-vinylphenyldimethoxymethylsilane and γ-mercaptopropyldimethoxy. Methylsilane, mercaptosiloxane such as γ-mercaptopropyltrimethoxysilane, trimethoxymethylsilane, triethoxyphenylsilane, tetra Tokishishiran, tetraethoxysilane, and a tetrabutoxysilane.

As the emulsifier used in the production of the polyorganosiloxane according to the present invention, an anionic emulsifier is preferable, and an emulsifier selected from sodium alkylbenzenesulfonate, sodium polyoxyethylene nonylphenyl ether sulfate, etc. Is used.
Particularly, sulfonic acid-based emulsifiers such as sodium alkylbenzene sulfonate and sodium lauryl sulfonate are preferable.

These emulsifiers are based on the siloxane mixture 10
It is used in the range of about 0.05 to 5 parts by weight with respect to 0 parts by weight. When the amount used is small, the dispersion state becomes unstable, and it becomes impossible to maintain the emulsified state with a fine particle size. Further, if the amount used is large, the coloring of the resin composition molded product due to the emulsifier becomes extremely large, which is inconvenient.

The method of mixing the siloxane mixture, the emulsifier, water and / or the acid catalyst includes mixing by high-speed stirring, mixing by a high pressure emulsifying device such as a homogenizer, and the method using a homogenizer is a polyorganosiloxane. This is a preferable method because the particle size distribution of the latex becomes small.

Examples of the acid catalyst used for polymerizing the polyorganosiloxane include sulfonic acids such as aliphatic sulfonic acid, aliphatic substituted benzenesulfonic acid and aliphatic substituted naphthalenesulfonic acid, and mineral acids such as sulfuric acid, hydrochloric acid and nitric acid. . These acid catalysts may be used alone or in combination of two or more. Among these, aliphatic-substituted benzenesulfonic acid is preferable, and n-dodecylbenzenesulfonic acid is particularly preferable, because it is also excellent in stabilizing the polyorganosiloxane latex. Also, n-
The combined use of dodecylbenzene sulfonic acid and a mineral acid such as sulfuric acid can reduce the coloring of the resin composition due to the emulsifier component of the polyorganosiloxane latex.

The polymerization temperature of polyorganosiloxane is 5
The temperature is preferably 0 ° C or higher, more preferably 80 ° C or higher.

The polymerization time of the polyorganosiloxane is 2 hours or more, more preferably 5 hours or more when the acid catalyst is mixed with the siloxane mixture, the emulsifier and water to be finely divided and polymerized. In the method of reducing the latex in which the siloxane mixture is made into fine particles, it is preferable to hold the latex for about 1 hour after the completion of the dropping of the latex.

The termination of the polymerization can be carried out by cooling the reaction solution and further neutralizing the latex with an alkaline substance such as caustic soda, caustic potash and sodium carbonate.

Polyalkyl (meth) acrylate (b-2) constituting the graft copolymer (B) according to the present invention
Is a polymer of an alkyl (meth) acrylate and a polyfunctional alkyl (meth) acrylate, and the composite rubber is a polyorganosiloxane (b-1) latex with an alkyl (meth) acrylate and Functional alkyl (meta)
It can be produced by impregnating an alkyl (meth) acrylate component consisting of an acrylate and then polymerizing. Examples of the alkyl (meth) acrylate include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and hexyl methacrylate. Examples thereof include alkyl methacrylates such as rate, 2-ethylhexyl methacrylate, and n-lauryl methacrylate, and especially n-butyl acrylate.
It is preferable to use Examples of polyfunctional alkyl (meth) acrylates include allyl methacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and 1,4-butylene. Examples thereof include glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate and the like. Further, the amount of the polyfunctional alkyl (meth) acrylate used is 0.1 to 20% by weight, preferably 0.2 to 20% by weight in the alkyl (meth) acrylate component.
It is 5% by weight, more preferably 0.2 to 1% by weight.
The alkyl (meth) acrylate and the polyfunctional alkyl (meth) acrylate may be used alone or in combination of two or more.

The composite rubber comprising the polyorganosiloxane and polyalkyl (meth) acrylate according to the present invention is
It can be prepared by adding the above-mentioned alkyl (meth) acrylate component to the latex of the polyorganosiloxane component and polymerizing it by allowing a usual radical polymerization initiator to act. As a method of adding the alkyl (meth) acrylate, there are a method of mixing with the latex of the polyorganosiloxane component at once and a method of dropping it into the latex of the polyorganosiloxane component at a constant rate. Considering the impact resistance of the resulting resin composition containing the graft copolymer, a method of mixing the latex of the polyorganosiloxane component at once is preferable. As the radical polymerization initiator used for polymerization, a peroxide, an azo-based initiator, or a redox-based initiator in which an oxidizing agent and a reducing agent are combined is used. Among these, a redox type initiator is preferable, and a sulfoxylate type initiator obtained by combining ferrous sulfate / ethylenediaminetetraacetic acid with a sodium salt / longalide / hydroperoxide is particularly preferable.

The graft copolymer (B) according to the present invention is
The polyorganosiloxane (b-
1) and an alkyl (meth) acrylate rubber (b-2) in a composite rubber, and (b-3) selected from aromatic alkenyl monomer, methacrylic acid ester, acrylic acid ester or vinyl cyanide monomer. Is a graft copolymer obtained by graft-polymerizing one or two or more types of monomers,
Among the monomers used in the graft polymerization, examples of the aromatic alkenyl monomer include styrene, α-methylstyrene, vinyltoluene, and the like, and examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, and the like.
2-Ethylhexyl methacrylate and the like, acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and the like, and vinyl cyanide compounds such as acrylonitrile and methacrylonitrile.

In the graft polymerization, one or more monomers selected from an aromatic alkenyl compound, a methacrylic acid ester, an acrylic acid ester or a vinyl cyanide compound is added to a latex of a composite rubber, and one step is carried out by a radical polymerization technique. Although it can be carried out in multiple steps or in multiple steps, it is preferable to carry out the polymerization in two or more steps in consideration of impact resistance and pigment coloring of the resulting resin composition containing the graft copolymer.

Further, various chain transfer agents for adjusting the molecular weight and graft ratio of the graft polymer can be added to the monomers used in the graft polymerization.

Polyorganosiloxane and alkyl (meth) constituting the graft copolymer (B) according to the present invention
The content of the composite rubber composed of an acrylate, considering both impact resistance and rigidity of the resin composition obtained,
The amount is preferably 0.5 to 70 parts by weight, more preferably 30 to 60 parts by weight, and further preferably 40 to 60 parts by weight, relative to 100 parts by weight of (B).

The particle size of the graft copolymer (B) prepared as described above is not particularly limited, but the impact resistance and pigment coloring property of the resin composition containing the obtained graft copolymer are not particularly limited. In consideration of both of the above, the weight average particle diameter is preferably 0.07 to 0.2 μm, and more preferably 0.10 to 0.15 μm.

After the graft polymerization is completed, the latex may be poured into hot water in which a metal salt such as calcium chloride or aluminum sulfate is dissolved, salted out and coagulated to separate and recover the graft copolymer. it can.

The thermoplastic resin composition according to the present invention is obtained by extruding the graft copolymer (A), the graft copolymer (B) and the copolymer (C) prepared by the above-mentioned method by a generally known kneading machine. It can be molded. Examples of such a molding machine include an extruder, an injection molding machine, a blow molding machine, a calendar molding machine and an inflation molding machine.

The thermoplastic resin composition according to the present invention is
Each of the above components (A), (B) and (C) is contained, and the blending amount of each component is 100 parts by weight of the copolymer (C) based on the graft copolymer (A) or the graft copolymer. It is necessary that the combined (B) be contained in an amount exceeding 40 parts by weight.

When the amount of both the graft copolymer (A) and the graft copolymer (B) is 40 parts by weight or less based on 100 parts by weight of the copolymer (C), the impact resistance of the thermoplastic resin composition obtained is high. Since it is low, it is not preferable.

Further, the thermoplastic resin composition according to the present invention can be used by blending a dye, a pigment, a stabilizer, a reinforcing agent, a filler, a flame retardant and the like, if necessary, in addition to the above resin components. .

The present invention will be described below with reference to examples. still,
In the Reference Examples, Examples and Comparative Examples, "parts" and "%" are "parts by weight" and "% by weight" unless otherwise specified.
Means

The weight average particle diameter of the polyorganosiloxane in the latex in the reference example and the weight average particle diameter of the graft copolymer in the latex in the examples are measured by using DLS-700 manufactured by Otsuka Electronics Co., Ltd. It was determined by the dynamic light scattering method.

The Izod impact strength in the examples and comparative examples was measured by the method according to ASTM D258.

The surface hardness (Rockwell hardness) in the examples and comparative examples was measured by the method according to ASTM D785.

The flexural modulus in the examples and comparative examples was measured by the method according to ASTM D790.

Regarding the appearance of molding, the same test piece used in the measurement of flexural modulus was evaluated by visual observation.

[0051]

【Example】

Reference Example 1 Polyorganosiloxane Latex L-
Preparation of 1 99.5 parts octamethylcyclotetrasiloxane, γ-
Methacryloxypropyl dimethoxymethylsilane 0.5
The parts were mixed to obtain 100 parts of a siloxane-based mixture. To this, 300 parts of distilled water in which 0.67 part of sodium dodecylbenzenesulfonate was dissolved was added, and the mixture was mixed with a homomixer to 1
After stirring for 2 minutes at 0000 rpm, a homogenizer
Through the resin once at a pressure of 300 kg / cm ² to obtain a stable premixed organosiloxane latex.

On the other hand, 10 parts of dodecylbenzenesulfonic acid and 90 parts of distilled water were injected into a reactor equipped with a reagent injection container, a cooling pipe, a jacket heater and a stirring device, and 1
A 0% by weight aqueous dodecylbenzenesulfonic acid solution was prepared.

With the aqueous solution heated to 85 ° C., the premixed organosiloxane latex was added dropwise over 4 hours, and after the completion of the addition, the temperature was maintained for 1 hour and cooled. The reaction was then neutralized with aqueous caustic soda.

The latex thus obtained was
When the solid content was determined by drying at 0 ° C. for 30 minutes, 17.
It was 7% by weight. The number average particle size of polyorganosiloxane in the latex was 0.05 μm.

Reference Example 2 Production of Composite Rubber Graft Copolymer S-1 The polyorgano obtained in Reference Example 1 was placed in a reactor equipped with a reagent injection container, a cooling pipe, a jacket heater and a stirrer. 56 parts of siloxane latex (L-1) and 0.3 part of sodium N-lauroylsarcosine were collected, and distilled water 25
After adding and mixing 0 parts, butyl acrylate 63.7
Parts, 0.4 parts allyl methacrylate, 0.1 parts 1,3-butylene glycol dimethacrylate and 0.15 parts cumene hydroperoxide.

By passing a nitrogen stream through this reactor, the atmosphere was replaced with nitrogen, and the temperature was raised to 60.degree. When the temperature of the internal liquid reached 60 ° C, 0.001 of ferrous sulfate was added.
01 parts, ethylenediaminetetraacetic acid disodium salt 0.0
An aqueous solution prepared by dissolving 003 parts and 0.24 parts of Rongalid in 10 parts of distilled water was added to initiate radical polymerization. The liquid temperature rose to 78 ° C. due to the polymerization of the acrylate component. This state was maintained for 1 hour to complete the polymerization of the acrylate component to obtain a latex of a composite rubber of polyorganosiloxane and butyl acrylate rubber.

After the liquid temperature inside the reactor dropped to 60 ° C.,
An aqueous solution prepared by dissolving 0.4 parts of Rongalid in 10 parts of distilled water was added, and then 11 parts of acrylonitrile and 3 parts of styrene.
A mixed solution of 3 parts and 0.23 part of cumene hydroperoxide was added dropwise for 2 hours for polymerization. After the dropping, the temperature of 60 ° C was maintained for 1 hour, and then 0.0002 parts of ferrous sulfate, 0.0006 parts of ethylenediaminetetraacetic acid disodium salt and 0.23 parts of rongalid were dissolved in 10 parts of distilled water. An aqueous solution was added, and then a mixed solution of 7.4 parts of acrylonitrile, 22.2 parts of styrene, and 0.13 part of cumene hydroperoxide was added dropwise over 2 hours for polymerization. After the completion of the dropping, the temperature of 60 ° C. is maintained for 1 hour and then cooled to obtain a latex of a graft copolymer obtained by graft-polymerizing an acrylonitrile-styrene copolymer on a composite rubber composed of polyorganosiloxane and butyl acrylate rubber. Obtained. The weight average particle diameter of the graft copolymer in the latex determined by the dynamic light scattering method was 0.13 μm. Then, 150 parts of an aqueous solution containing 7.5% by weight of aluminum sulfate was dissolved in 6 parts.
It heated at 0 degreeC and stirred. 100 parts of the latex of the graft copolymer was gradually dropped into this and coagulated. Then, the precipitate was separated, washed and dried to obtain a graft copolymer.

(Examples 1 to 3 and Comparative Examples 1 to 3) The following components were used in Examples and Comparative Examples.

Component (A) (ABS graft polymer):
ABS graft-polymerized with a mixture of acrylonitrile (15 parts) and styrene (35 parts) to 50 parts of polybutadiene
Graft polymer (average particle size 0.3 μm, acetone insoluble content 70% by weight) Component (B) (composite rubber-based graft copolymer): Reference Example 2
In the prepared composite rubber-based copolymer component (C) (SAN resin): polymerized by a mixture of 70 parts of styrene and 30 parts of acrylonitrile suspension polymerization method, a reduced viscosity measured in dimethylformamide solution (η _SP / C ) is 0.60 SAN resins above (a), (B) and (each component of C) were mixed at a ratio (weight ratio) shown in Table 1, Adekasutaburu C (Asahi Denka (strain as further heat stabilizer )), 0.4 parts of barium stearate as a release agent, and 0.4 parts of EBS as a lubricant, respectively, and mixed, and the cylinder temperature is set to 230 ° C. It shape | molded with the machine and produced the pellet. The pellet is then cylinder-
Injection molding was performed at a set temperature of 230 ° C and a mold temperature of 60 ° C to obtain a test piece for evaluating physical properties. Table 1 shows the results of measurement of Izod impact strength, Rockwell hardness and flexural modulus of each of the obtained test pieces.

[0060]

[Table 1]

Reference Examples 3 to 4 Preparation of ABS Resin and Measurement of Physical Properties The component (A) ABS graft polymer and the component (C) SAN resin used in Examples and Comparative Examples were mixed in the proportions shown in Table 1, Adecastable C (made by Asahi Denka Co., Ltd.) 0.3 part as a heat stabilizer, barium stearate 0.4 part as a release agent, and EBS as a lubricant.
0.4 parts of each was added and mixed, and a cylinder temperature of 23
It shape | molded with the single screw extruder set to 0 degreeC, and the pellet was produced. This pellet is then placed in the cylinder-set temperature 230.
Injection molding at a temperature of 60 ° C. and a mold temperature of 60 ° C. to obtain a test piece for evaluating physical properties. Table 1 shows the results of measurement of Izod impact strength, Rockwell hardness and flexural modulus of each of the obtained test pieces.

From the examples, comparative examples and reference examples, the following facts became clear.

1) (C) SAN resin 10 of Examples 1 to 3
The resin composition in which either (A) ABS graft polymer or (B) composite rubber-based graft copolymer was added in an amount exceeding 40 parts by weight based on 0 part by weight was the same rubber as in Reference Example 3. Compared with the ABS resin which does not contain the content of the composite rubber graft copolymer, the Rockwell hardness and the flexural modulus are almost the same, and the Izod impact strength is high.

2) On the other hand, 40 parts of each of (A) ABS graft polymer and (B) composite rubber graft copolymer were added to 100 parts by weight of (C) SAN resin of Comparative Examples 1 to 3.
The resin composition blended in the range of parts by weight or less has almost the same Rockwell hardness and flexural modulus as compared to the ABS resin shown in Reference Example 4 which does not contain the composite rubber-based graft copolymer having the same rubber content. However, the Izod impact strength is low.

3) The resin compositions shown in the examples have a good molding appearance.

[0066]

As described above, the present invention has the following particularly remarkable effects and its industrial utility value is extremely large.

1) The resin composition according to the present invention has an excellent balance of impact resistance, surface hardness and rigidity.

2) In particular, this balance between Izod impact strength and rigidity is at a very high level which cannot be obtained by the conventionally known ABS resin, and its utility value as various industrial materials is extremely high.

Front page continuation (72) Inventor Sumi Yangi 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory

Claims (1)

[Claims] 1. A thermoplastic resin composition comprising the following (A), (B) and (C), wherein a (C) copolymer 100 is used.
A thermoplastic resin composition comprising (A) or (B) in an amount of more than 40 parts by weight based on parts by weight. (A) A graft copolymer obtained by grafting a rubber-like polymer with a monomer mixture of an aromatic vinyl monomer, a vinyl cyanide monomer and a vinyl monomer copolymerizable therewith. (B) (b-1) polyorganosiloxane and (b-
2) One or two kinds selected from (b-3) aromatic alkenyl monomer, methacrylic acid ester, acrylic acid ester or vinyl cyanide monomer in a composite rubber composed of polyalkyl (meth) acrylate. A graft copolymer in which the above monomers are graft-polymerized. (C) A copolymer comprising an aromatic alkenyl monomer component, a vinyl cyanide monomer component and a vinyl monomer component copolymerizable therewith as a constituent component of the copolymer.